This invention relates to seats for vehicles including occupant protection apparatus and more particularly, to seat including an airbag for supporting an occupant""s head and neck during a rear impact to prevent whiplash injuries to the occupant.
Approximately 100,000 rear impacts per year result in whiplash injuries to the vehicle occupants. Most of these injuries could be prevented if the headrest were properly positioned behind the head of the occupant and if it had the correct contour to properly support the head and neck of the occupant. Whiplash injuries are the most expensive automobile accident injury even though these injuries are usually are not life threatening and are usually classified as minor.
A good discussion of the causes of whiplash injuries in motor vehicle accidents can be found in Dellanno et al, U.S. Pat. Nos. 5,181,763 and 5,290,091, and Dellanno, U.S. Pat. Nos. 5,580,124, 5,769,489 and 5,961,182, which are included herein by reference, as well as many other technical papers. These patents discuss a novel automatic adjustable headrest to minimize such injuries. However, these patents assume that the headrest is properly positioned relative to the head of the occupant. A survey has shown that as many as 95% of automobiles do not have the headrest properly positioned. These patents also assume that all occupants have approximately the same contour of the neck and head. Observations of humans, on the other hand, show that significant differences occur where the back of some people""s heads is almost in the same plane as the that of their neck and shoulders, while other people have substantially the opposite case, that is, their neck extends significantly forward of their head back and shoulders.
One proposed attempt at solving the problem where the headrest is not properly positioned uses a conventional crash sensor which senses the crash after impact and a headrest composed of two portions, a fixed portion and a movable portion. During a rear impact, a sensor senses the crash and pyrotechnically deploys a portion of the headrest toward the occupant. This system has the following potential problems:
An occupant can get a whiplash injury in fairly low velocity rear impacts; thus, either the system will not protect occupants in such accidents or there will be a large number of low velocity deployments with the resulting significant repair expense.
2) If the portion of the headrest which is propelled toward the occupant has significant mass, that is if it is other than an airbag type device, there is a risk that it will injure the occupant. This is especially true if the system has no method of sensing and adjusting for the position of the occupant.
3) If the system does not also have a system which pre-positions the headrest to the proximity of the occupant""s head, it will also not be affective when the occupant""s head is forward due to pre-crash braking, for example, or for different sized occupants.
A variation of this approach uses an airbag positioned in the headrest which is activated by a rear impact crash sensor. This system suffers the same problems as the pyrotechnically deployed headrest portion. Unless the headrest is pre-positioned, there is a risk for the out-of-position occupant.
U.S. Pat. No. 5,833,312 to Lenz describes several methods for protecting an occupant from whiplash injuries using the motion of the occupant loading the seat back to stretch a canvas or deploy an airbag using fluid contained within a bag inside the seat back. In the latter case, the airbag deploys out of the top of the seat back and between the occupant""s head and the headrest. The system is based on the proposed fact that: xe2x80x9c[F] irstly the lower part of the body reacts and is pressed, by a heavy force, against the lower part of the seat back, thereafter the upper part of the body trunk is pressed back, and finally the back of the head and the head is thrown back against the upper part of the seat back . . . xe2x80x9d (Col. 2 lines 47-53). Actually this does not appear to be what occurs. Instead, the vehicle, and thus the seat that is attached to it, begins to decelerate while the occupant continues at its pre-crash velocity. Those parts of the occupant that are in contact with the seat experience a force from the seat and begin to slow down while other parts, the head for example continue moving at the pre crash velocity. In other words, all parts of the body are xe2x80x9cthrown backxe2x80x9d at the same time. That is, they all have the same relative velocity relative to the seat until acted on by the seat itself. Although there will be some mechanical advantage due to the fact that the area in contact with the occupant""s back will generally be greater than the area needed to support his or her head, there generally will not be sufficient motion of the back to pump sufficient gas into the airbag to cause it to be projected in between the head that is not rapidly moving toward the headrest. In some cases, the occupant""s head is very close to the headrest and in others it is far away. For all cases except when the occupant""s head is very far away, there is insufficient time for motion of the occupant""s back to pump air and inflate the airbag and position it between the head and the headrest. Thus, not only will the occupant impact the headrest and receive whiplash injuries, but it will also receive an additional impact from the deploying airbag.
Lenz also suggests that for those cases where additional deployment speed is required, that the output from a crash sensor could be used in conjunction with a pyrotechnic element. Since he does not mention anticipatory crash sensor, which were not believed to be available at the time of the filing of the Lenz patent application, it must be assumed that a conventional crash sensor is contemplated. As discussed herein, this is either too slow or unreliable since if it is set so sensitive that it will work for low speed impacts where many whiplash injuries occur, there will be many deployments and the resulting high repair costs. For higher speed crashes, the deployment time will be too slow based on the close position of the occupant to the airbag. Thus, if a crash sensor is used, it must be an anticipatory crash sensor as disclosed herein.
It is an object of the present invention to provide new and improved headrests for seats in a vehicle which offer protection for an occupant in the event of a crash involving the vehicle.
It is another object of the present invention to provide new and improved seats for vehicles which offer protection for an occupant in the event of a crash involving the vehicle.
It is still another object of the present invention to provide new and improved cushioning arrangements for vehicles and protection systems including cushioning arrangements which provide protection for occupants in the event of a crash involving the vehicle.
It is yet another object of the present invention to provide new and improved cushioning arrangements for vehicles and protection systems including cushioning arrangements which provide protection for occupants in the event of a collision into the rear of the vehicle, i.e., a rear impact.
It is still another object of the present invention to provide new and improved headrests for seats in vehicles which include a fluid-containing bag which changes its shape, e.g., in the event of a crash, so as to approximately conform to the head and neck of the occupant and thereby provide a force on the head and neck of the occupant to substantially accelerate both the head and neck at substantially the same acceleration in order to minimize whiplash injuries.
It is yet another object of the present invention to provide new and improved cushioning arrangements for vehicles and protection systems including cushioning arrangements which include a fluid-containing bag having an associated flow restriction to permit a controlled flow of air out of the bag upon impact of an object against the cushioning arrangement to thereby dampen the impact of the object against the cushioning arrangement.
It is yet another object of the present invention to provide new and improved headrests for vehicles which include a fluid-containing bag having an associated flow restriction to permit a controlled flow of air out of the bag upon impact of an object against the headrest to thereby dampen the impact of the object against the headrest.
It is yet another object of the present invention to provide new and improved vehicular systems which reduce whiplash injuries from rear impacts of a vehicle by causing the headrest to be automatically positioned proximate to the occupant""s head.
It is yet another object of the present invention to provide new and improved vehicular systems to position a headrest proximate to the head of a vehicle occupant prior to a pending impact into the rear of a vehicle.
It is yet another object of the present invention to provide a passive occupant protection system which is deployed in time to protect an occupant in a rear impact and resets without the need for repair or replacement of the system.
It is yet another object of the present invention to provide a simple anticipatory sensor system for use with an adjustable headrest to predict a rear impact.
It is yet another object of the present invention to provide a method and arrangement for protecting an occupant in a vehicle during a crash involving the vehicle using an anticipatory sensor system and a cushioning arrangement including a fluid-containing bag which is brought closer toward the occupant or ideally in contact with the occupant prior to or coincident with the crash. The bag would then conform to the portion of the occupant with which it is in contact.
It is yet another object of the present invention to provide an automatically adjusting system which conforms to the head and neck geometry of an occupant regardless of the occupant""s particular morphology to properly support both the head and neck.
Other objects and advantages of this invention will become apparent from the disclosure which follows.
In order to achieve at least one of the foregoing objects, a headrest for a seat of a vehicle in accordance with the invention comprises a frame attachable to the seat and a fluid-containing bag attached to the frame. The bag is structured and arranged to allow movement of the fluid within the bag to thereby alter the shape of the bag and enable the bag to conform to the head and neck of an occupant. A deformable cover may substantially surround the bag such that the bag is within the seat, i.e., an outer surface of the bag is not exposed to the atmosphere. The cover is elastically deformable in response to changes in pressure in the bag. The frame may be made of a rigid material. The bag can contain cell foam having openings (open cell foam), which in a static state, determines the shape of the bag. The fluid in the bag may be air, i.e., an airbag.
To provide the elastic deformation of the cover, the cover may include stretch seams at one or more locations. Preferably, the stretch seams should be placed on the side(s) of the headrest which will contour to the shape of the occupant""s head and neck upon impact.
The bag may include constraining means for constraining flow of fluid from an upper portion of the headrest to a lower portion of the headrest. Such constraining means may comprise open cell foam possibly with channels extending in a direction from a top of the headrest to a bottom of the headrest. In the alternative, the properties of the foam may be controlled to get the desired flow rate and possibly flow direction. The constraining means are structured and arranged such that when the upper portion contracts, the lower portion expands. Also, the constraining means may be designed so that when the upper portion expands, the lower portion contracts.
The cover and bag are structured and arranged such that when an occupant impacts the headrest, fluid within the bag flows substantially within the bag to change the shape of the bag so as to approximately conform to the head and neck of the occupant thereby providing a force on the head and neck of the occupant to substantially accelerate both the head and neck at substantially the same acceleration in order to minimize whiplash injuries.
The bag preferably includes a flow restriction which permits a controlled flow of fluid out of the bag upon impact of an object with the headrest to thereby dampen the impact of the object with the headrest.
A seat of a vehicle in accordance with the invention comprises a seat frame, a bottom cushion, a back cushion cooperating to support an occupant and a headrest attached to the seat frame. The headrest is as in any of the embodiments described immediately above.
A cushioning arrangement for protecting an occupant in a crash in accordance with the invention comprises a frame coupled to the vehicle and a fluid-containing bag attached to the frame. The bag is structured and arranged to allow movement of the fluid within the bag to thereby alter the shape of the bag and enable the bag to conform to a portion of the occupant engaging the cushioning arrangement. The cushioning arrangement should be arranged relative to the occupant such that the bag impacts the occupant during the crash. As used here (and often elsewhere in this application), xe2x80x9cimpactxe2x80x9d does not necessarily imply direct contact between the occupant and the bag but rather may be considered the exertion of pressure against the bag caused by contact of the occupant with the outer surface of the cushioning arrangement which is transmitted to the bag. The cushioning arrangement can also include a deformable cover substantially surrounding the bag. The cover is elastically deformable in response to changes in pressure in the bag. The frame may be coupled to a seat of the vehicle and extends upward from a top of the seat such that the cushioning arrangement constitutes a headrest. In the alternative, the cushioning arrangement can be used anywhere in a vehicle in a position in which the occupant will potentially impact it during the crash. The bag and headrest may be as in any of the embodiments described above.
A protection system for protecting an occupant in a crash in accordance with the invention comprises an anticipatory crash sensor for determining that a crash involving the vehicle is about to occur, and a movable cushioning arrangement coupled to the anticipatory crash sensor. The cushioning arrangement is movable toward a likely position of the occupant, preferably in actual contact with the occupant, upon a determination by the anticipatory crash sensor that a crash involving the vehicle is about to occur. The cushioning arrangement comprises a frame coupled to the vehicle, and a fluid-containing bag attached to the frame. The bag is structured and arranged to allow movement of the fluid within the bag to thereby alter the shape of the bag and enable the bag to conform to the occupant. The cushioning arrangement and its parts may be as described in any of the embodiments above.
The anticipatory crash sensor may be arranged to determine that the crash involving the vehicle is a rear impact. In this case, it could comprise a transmitter/receiver arrangement mounted at the rear of the vehicle.
To provide for movement of the cushioning arrangement, displacement means are provided, e.g., a system of servo-motors, screws and support rods, and a control unit is coupled to the anticipatory crash sensor and the displacement means. The control unit controls the displacement means to move the cushioning arrangement based on the determination by the anticipatory crash sensor that a crash involving the vehicle is about to occur.
A method for protecting an occupant in an impact comprises the steps of determining that a crash involving the vehicle is about to occur, and moving a cushioning arrangement into contact with the occupant upon a determination that a crash involving the vehicle is about to occur. The cushioning arrangement comprises a frame coupled to the vehicle and a fluid-containing bag attached directly or indirectly to the frame. The bag is structured and arranged to allow movement of the fluid within the bag to thereby alter the shape of the bag and enable the bag to conform to the occupant. The cushioning arrangement may be as in any of the embodiments described above. The step of moving the cushioning arrangement into contact with the occupant may comprise the steps of moving the cushioning arrangement toward the occupant, detecting when the cushioning arrangement comes into contact with the occupant and then ceasing movement of the cushioning arrangement. The step of detecting when the cushioning arrangement comes into contact with the occupant may comprise the step of arranging a contact switch in connection with the cushioning arrangement.
Also disclosed herein is a headrest and headrest positioning system which reduce whiplash injuries from rear impacts by properly positioning the headrest behind the occupant""s head either continuously, or just prior to and in anticipation of, the vehicle impact and then properly supports both the head and neck. Sensors determine the location of the occupant""s head and motors move the headrest both up and down and forward and back as needed. In one implementation, the headrest is continuously adjusted to maintain a proper orientation of the headrest to the rear of the occupant""s head. In another implementation, an anticipatory crash sensor, such as described in copending U.S. patent application Ser. No. 09/307,883, is used to predict that a rear impact is about to occur, in which event, the headrest is moved proximate to the occupant.
Also disclosed herein is an apparatus for determining the location of the head of the occupant in the presence of objects which obscure the head. Such an apparatus comprises transmitter means for illuminating a selective portion of the occupant and the head-obscuring objects,in the vicinity of the head, sensor means for receiving illumination reflected from or modified by the occupant and the head-obscuring objects and generating a signal representative of the distance from the sensor means to the illuminated portion of the occupant and the head-obscuring objects, selective portion changing means for changing the illuminated portion of the occupant and the head-obscuring objects which is illuminated by the transmitter means and a processor. The processor comprises means for sequentially operating the selective portion changing means so as to illuminate different portions of the occupant and the head-obscuring objects, and pattern recognition means for determining the location of the head from the signals representative of the distance from the sensor means to the different selective portions of the occupant and the head-obscuring objects. The pattern recognition means may comprise a neural network.
In some embodiments of the invention, the head-obscuring objects comprise items from the class containing clothing and hair. The pattern recognition means may be arranged to determine the location of the approximate longitudinal location of the head from the headrest. If one or more airbags is mounted within the vehicle, the head location system may include means for determining the location of the head relative to the airbag. The transmitter means may comprise an ultrasonic transmitter arranged in the headrest and the sensor means may also be arranged in the headrest, possibly vertically spaced from the transmitter means. In the alternative, the transmitter means and sensor means may comprise a single transducer. The selective portion changing means may comprise a control module coupled to the transmitter means and the sensor means and servomotors for adjusting the position of the headrest.
Illumination as used herein is any form of radiation which is introduced into a volume of which contains the head of an occupant and includes, but it is not limited to, electromagnetic radiation from below one kHz to above ultraviolet optical radiation (1016 Hz) and ultrasonic radiation. Thus, any system, such as a capacitive system, which uses a varying electromagnetic field, or equivalently electromagnetic waves, is meant to be included by the term illumination as used herein. By reflected radiation, it is meant the radiation that is sensed by the device that comes from the volume occupied by the head, or other part, of an occupant and indicates the presence of that part of the occupant. Examples of such systems are ultrasonic transmitters and receivers placed in the headrest of the vehicle seat, capacitive sensors placed in the headrest or other appropriate location (or a combination of locations such as one plate of the capacitor being placed in the vehicle seat and the other in the headliner), radar, far or near frequency infrared, visible light, ultraviolet, etc.